Worth is something only YOU can determine.
If you have a need now, then upgrade now.
Your 4790K is still a very good processor, particularly if overclocked.
You have 8 threads and a good single thread clock rate.
For most games, the single thread clock rate is most important.
Nobody knows what next gen ryzen will bring, and at what price.
AMD has no incentive to give things away.
Your i7-4790K has 8 threads and a passmark rating of 11239 and a single thread rating of 2824. very good for gaming.
Today's 2700X for example has a passmark rating of 16986. That is when all 16 threads are fully utilized.
The single thread rating is 2193, not as good for gaming.
Expect ryzen 3000 to do better.
You might wonder just how many threads are useful to you.
Try experimenting with removing one or more cores/threads. You can do this in the windows msconfig boot advanced options option.
You will need to reboot for the change to take effect. Set the number of threads to less than you have.
This will tell you how sensitive your games are to the benefits of many threads.
If you see little difference, your game does not need all the threads you have.